ABSTRACT
Objective: Prenatal providers are pregnant women's most trusted sources of health information, and a provider's recommendation is a strong predictor of maternal vaccine receipt. However, other ways women prefer receiving vaccine-related information from prenatal providers, aside from face-to-face conversations, is unclear. This study explores what secondary communication methods are preferred for receiving maternal vaccine-related information. Study design: Obstetric patients at four prenatal clinics around Atlanta, Georgia received a 27-item survey between May 5th, 2016 and June 15th, 2016. Participants were asked about sources they currently use to obtain prenatal health information and their preferences for receiving vaccine-related information from providers. Descriptive statistics were calculated and chi-square tests were used to evaluate associations between participant characteristics and outcomes. Results: Women primarily reported using the CDC website (57.7%) and pregnancy-related websites (53.0%) to obtain vaccine information. Apart from clinical conversations, educational brochures (64.9%) and e-mails (54.7%) were the preferred methods of receiving vaccine information from providers, followed by their provider's practice website (42.1%). Communication preferences and interest in maternal immunization varied by race/ethnicity, age and education; white women were twice as likely to want information on a provider's practice website compared to African-American women (OR = 2.06; 95% CI: 1.31, 3.25). Conclusions: Pregnant women use the Internet for information about vaccines, but they still value input from their providers. While e-mails and brochures were the preferred secondary modes of receiving information, a provider's existing practice website offers a potential communications medium that capitalizes on women's information seeking behaviors and preferences while limiting burden on providers.
Introduction
Pregnant women and their infants are at a higher risk of developing complications from influenza and pertussis (whooping cough).Citation1-4 Because of this, the Centers for Disease Control and Prevention (CDC) and the American Congress of Obstetricians and Gynecologists (ACOG) recommend that pregnant women receive the influenza and the tetanus, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccines during pregnancy.Citation5 Many of the guidelines and recommendations issued by the CDC have been endorsed and promoted by ACOG. Pregnant women have been the focus of communicating the benefits of immunization and disease risks in order to address the higher risk of complications that pregnant women and their infants face.Citation6
Despite recommendations from CDC and ACOG, maternal immunization rates still remain low. From most recent estimates, approximately 36% of pregnant women receive the flu shot during pregnancy and 48.8% receive the Tdap vaccine.Citation7,Citation8 Barriers to vaccination include a lack of knowledge about the safety of the vaccines or severity of the diseases during or after pregnancy.Citation9-15 Lack of an explicit provider recommendation to receive a vaccine and limited access to the vaccine in obstetric provider offices are also cited as barriers.Citation9,Citation10,Citation12,Citation14-16
It is well documented and widely accepted that prenatal care providers play an essential role in vaccine promotion; one of the most significant predictors of vaccine receipt is provider recommendation of the vaccine.Citation15-20 While we know provider-to-patient communication is important, exactly how providers should communicate with their patients has received less attention. Ideally, providers would have in-depth in-person discussions with each patient about relevant heath topics, but ample clinic time with each patient is often cited as a limitation to conveying all relevant information.Citation21-26 Also, the frequency of prenatal care visits is weighted towards the end of pregnancy, when the window of opportunity may have passed for education about time-sensitive topics like seasonal influenza vaccination.
Since there may be inadequate time to discuss vaccinations with every patient, knowing other ways women prefer to receive information from their prenatal care providers may be helpful for managing and preempting information requests. Through a survey of over 400 pregnant women, this study aimed to assess pregnant women's preferences for receiving information on routine maternal vaccinations, aside from verbal exchanges with their providers. The study also sought to understand women's current information seeking habits regarding maternal vaccination as compared to other prenatal care topics, like Zika virus disease and safe medication use during pregnancy.
Results
Of the 600 blank surveys delivered to the clinics, 408 surveys were returned, all of which were completed in English.Citation27 The demographic characteristics of the study population have been previously published.Citation27 Nearly two-thirds of respondents indicated that they were interested or very interested in information about maternal vaccination (64.4%). Interest in information about vaccines was associated with age, race and higher levels of education (). Women over 35 years old were nearly two times more likely than younger women to be interested in vaccine information, and white women were over twice as likely to be interested in vaccine information than African American women (women over 35 years old (67.9%), women under 30 years old (53%); OR = 1.87, 95% CI: 1.11, 3.16; white women (73.9%), African American women (55.0%); OR = 2.26, 95% CI: 1.40, 3.63). Interest among Hispanic women was not significantly higher than interest among African American women (Hispanic women (75.0%), African American women (55.0%); OR = 2.38, 95% CI: 0.82, 6.90). Compared to women without a college degree, women with at least a Bachelor's degree were over three times more likely to be interested in vaccine-related information (women with at least a Bachelor's degree (71.9%), women without a degree (44.1%); OR = 3.25, 95% CI: 2.08, 5.08). Although age, race/ethnicity and education level varied between the four study sites, adjusting for study site did not alter the relationship between age, race/ethnicity or education and interest.
Table 1. Interest in information about maternal vaccinations by selected patient characteristics.
Provider type was also associated with interest in information about maternal vaccines; women who saw an obstetrician/gynecologist (ob/gyn), either alone or in combination with a midwife, were two to four times more likely to be interested in information about vaccines than women who only reported seeing a midwife (ob/gyn only (65.9%): OR = 2.60, 95% CI: 1.40, 4.85; ob/gyn & midwife (76.9%): OR = 4.50, 95% CI: 1.09, 18.50; midwife only (42.6%)).
Only about half of women surveyed recalled discussing maternal vaccination with their providers (53.8%), compared to 82.0% of women who recalled discussing safe medications. However, compared to women in their first or second trimesters, a higher proportion of women in their third trimester recalled discussing maternal vaccination with their provider (first trimester: 30.2%, second trimester: 29.3%, third trimester: 76.0%, p-value < 0.0001). Although women who saw an ob/gyn for their prenatal care were more interested in information about vaccination, there was no meaningful difference by provider type in the proportions of women who reported having discussed the topic with their provider. (ob/gyn: 54.3%; midwife: 58.7%; p = 0.9709).
Aside from verbal communications with their prenatal providers, the top resources that women reported currently using to obtain information about maternal vaccines were the CDC website (57.7%), other pregnancy-related websites (53.0%) and their obstetric provider's own practice website (35.4%) (). Currently used sources did not vary meaningfully by age; however, women with at least a Bachelor's degree were nearly 3.5 times more likely to use the CDC website to obtain vaccine information than were women without a Bachelor's degree (women with at least a Bachelor's degree (66.8%), women without a Bachelor's degree (36.8%); OR = 3.46; 95% CI: 2.21, 5.43). White women were over 4 times as likely to use the CDC website than were African American women (white women (73.2%), African American women (39.3%); OR = 4.21; 95% CI: 2.61, 6.77), who tended to prefer other pregnancy websites (56.6%) to the CDC website (39.3%). Practice and age were considered as confounders for the relationship between education and information preferences, however, adjusting for practice or age did not alter the relationship between the selected demographic characteristics and information preferences.
Figure 1. Currently used secondary communication modes for maternal vaccine information.
When asked how they would like to receive information about maternal vaccination from their prenatal care providers, women were most interested in educational brochures (64.9%), e-mails (54.7%), and a vaccine-related section on their provider's own website (42.1%) (). Although these findings were similar by race/ethnicity, white women were twice as likely as African American women to be interested in a vaccine section on their provider's practice website (OR = 2.06; 95% CI: 1.31, 3.25). There was little desire in being able to obtain vaccine information via a practice-sponsored Facebook page (7.7%) or Twitter feed (1.2%). Similar communications preferences were observed for the topics of Zika virus and safe medications during pregnancy.Citation27
Figure 2. Preferred secondary communication modes for maternal vaccine information.
Discussion
In recent years, it has become apparent that the amount of clinic time providers spend with patients is dwindling. The Medscape 2016 Physicians Compensation Report, a survey of approximately 20,000 physicians of all specialties, found that approximately half of physicians reported spending 16 minutes or less with patients, and the duration of clinical encounters can be reduced even further when a clinic falls behind schedule.Citation28 Unfortunately, while it is true pregnant women are seen multiple times during their pregnancy – a schedule that may allow for repeatedly bringing up a given topic – the reality is that these increasingly short in-person encounters do not bode well for adequately discussing topics like maternal influenza and Tdap vaccination. Both topics are important from a disease prevention perspective, but can be riddled with misinformation on the Internet and elsewhere.Citation29,Citation30 Additionally, as evidenced by the substantial proportion of women in our study who reported not discussing maternal vaccines with their providers, providers may not be relaying enough information about maternal vaccination to their patients. Alternatively, they may not be promoting the vaccines early enough in pregnancy or in ways the women are internalizing. With vaccination now a routine part of obstetric care, it is imperative that providers look to expand and refine the way they communicate with patients about vaccines and perhaps tailor their vaccine communication strategies according to the preferences of their own patient populations.
In this study, we found that aside from talking directly with their prenatal care provider about vaccines, the majority of women wanted to receive vaccine related information in brochures and emails from their prenatal care providers. Although this preference for educational brochures and e-mails did not vary meaningfully by race/ethnicity, we did find white women to be twice as likely as African American women to be interested in finding vaccine information in a section on their prenatal provider's practice website. This difference reveals that communication preferences may in fact differ by key patient characteristics or demographics, and providers may want to be cognizant of these differences before investing time and energy into certain secondary communication avenues. While it is certainly not feasible to perfectly tailor educational content to every patient's unique communication preferences, it may be worthwhile to get at least a general understanding of the preferences of the majority of the patients a practice serves.
Although brochures and e-mails were the most preferred secondary modes for receiving vaccine information from providers, it is worth noting that both brochures and emails either require a clinical encounter or put substantial burden on providers. While e-mails can deliver health information directly from the provider to the patient, maintaining an up-to-date database of patient emails can be burdensome on providers and their staff. Brochures can be convenient, and while organizations like CDC and ACOG have produced excellent brochure-type resources for obstetric care providers to use, they still require a physical encounter for distribution and do not necessarily align with women's current electronic information seeking habits. In congruence with other studies that have explored pregnant women's health information seeking behaviors, women in this study also turned primarily to the Internet for vaccine-related information.Citation22,Citation31,Citation32 Most women accessed the CDC website or other pregnancy-related websites, while social media outlets like Twitter and Facebook were substantially less popular.
After the CDC website and other pregnancy-related websites, the third most popular source for obtaining vaccine-related information was their prenatal care provider's own website. It is this platform that may offer the most practical and useful solution to bolstering providers' educational reach to their patients. This is because provider websites marry two important patient preferences into one modality: a desire to access evidence-based information online and having that information be endorsed by their own provider. Upon analyzing our survey results for Zika-related communication preferences, we found that the most important characteristics of educational content received from their providers were being evidence-based and endorsed by their own prenatal care provider.Citation27 These findings align with the numerous other studies that have also revealed that women value vaccine information or recommendations most when they come from their own provider.Citation14-20,Citation33 Providers' own practice websites allow providers to share reputable, evidence-based information and put their own stamp of approval on that information. This capability is particularly important for vaccine information, as anti-vaccine activists are known for using a variety of tricks and tactics to deliberately spread misinformation about vaccines to individuals who may be turning to the Internet for vaccine information.Citation29,Citation30 With more than 85% of obstetric providers in the U.S. already hosting websites, this should be a particularly appealing avenue for patient education about vaccines.Citation34
Unfortunately, provider practice websites are not being utilized to their fullest potential. In this study, we found that approximately 35% of women are already looking to their provider's website as a source of information on maternal vaccination and safe medications, but that information on both topics may not be readily available. From a 2014 national cross-sectional survey of 1,000 prenatal care websites, only 22.8% of the websites examined had any information available on antenatal vaccination.Citation34 Thirty-six percent had information on safe medications during pregnancy. While the greater prevalence of information on safe medications aligns with a greater interest in the topic as compared to vaccines (for example, 83.7% of women in our survey indicated an interest in information about safe medications versus 64.4% indicating interest in information on maternal vaccines), the discrepancies between interest and availability of the information on practice websites – for either topic – is substantial and may be important to rectify.
The study has some important limitations. In addition to having been based on responses from a highly educated, literate patient population, our respondents were older (most over the age of 30), and our sample was almost exclusively white and African American. Only 4.0% of those surveyed were Hispanic.Citation27 According to a survey conducted by the Pew Research Center in 2008, approximately one quarter of pregnant women surveyed at the time identified as Hispanic while only 15% identified as black.Citation35 These characteristics from our sample could have biased the results towards individuals more likely to turn to the Internet for health information. Additionally, since all practices included in the study were located in the greater Atlanta area, the proportion of women aware of the CDC as a reputable resource for information on prenatal care topics like vaccines may have been greater than a similar sample recruited elsewhere. Despite this fact, previous studies have not found substantial differences in the information-seeking preferences of pregnant women by region or country.Citation26,Citation36 The four practices included in the study were all specifically prenatal care locations with obstetricians and midwives as the sources of antenatal care. In other locations, there may be other sources of prenatal care. Additionally, given the high prevalence of the outcomes in this study the prevalence odds ratios calculated do not approximate the prevalence ratio. However, although the prevalence odds ratio may overestimate the magnitude of the association in cases where there is a high prevalence, the direction of the association remains the same.Citation37
In conclusion, while we confirmed that many pregnant women use the Internet as a primary source of information about maternal vaccines during pregnancy, they still place value on their own provider's endorsement of vaccine information. Aside from verbal discussions with their providers about vaccines, women prefer receiving information in the form of e-mails, brochures or a vaccine-related section on their provider's practice website. While all three of these modalities can be useful, existing practices websites potentially offer the most promise in so far as they provide an appealing balance between aligning with pre-existing health seeking-behaviors, patient preferences, and provider burden.
Materials and methods
The survey methods employed in this study have been previously described.Citation27 In short, we distributed 100 hard-copy surveys (available in both English and Spanish) to each of 4 obstetric care practices in Atlanta, GA that volunteered to participate in this study. Because the primary purpose of our survey was to rapidly ascertain women's communication preferences about Zika virus disease, surveys were distributed between May 5th, 2016 and June 20th, 2016. All obstetric patients visiting the clinics during this timeframe were offered the survey by front-desk staff upon check-in and instructed to return the survey back to the front desk upon completion. No data was collected on how many women checked in at the clinics between the two dates or on any non-responders. Because the survey collected no identifying information, the study was granted exempt status by the Emory University Institutional Review Board.
All data analyses were conducted using SAS 9.3 (Cary, NC). Women's preferences for receiving information about maternal vaccines were analyzed by age, race, education, provider type and trimester. In addition to women's communication preferences, we also ascertained women's current sources for obtaining vaccine information, level of interest in obtaining information about vaccines, and experiences discussing vaccines with their obstetric care provider. Unadjusted and adjusted logistic regression models were used to calculate odds ratios and 95% confidence intervals for multi-level covariates. Chi-squared tests and Fisher's exact tests were used to calculate the statistical significance of associations of interest. Statistical significance was defined as a p-value <0.05 or a 95% confidence interval that does not include 1.0. Frequency procedures in SAS were used to calculate odds ratios and 95% confidence intervals for dichotomous covariates. For our analyses, interest in maternal vaccines was dichotomized; women were considered ‘interested’ if they indicated that they were ‘very interested’ or ‘interested’ in information about maternal vaccines. They were categorized as ‘not interested’ if they indicated being ‘not interested at all’, ‘a little interested’ or ‘neutral.’ Similarly, education was dichotomized with women having received a Bachelor's degree or higher-level degree categorized as ‘Women with at least a Bachelor's degree’ and all other women as ‘Women without a Bachelor's degree’. Age was divided into three categories, one including women aged 35 years or older, one for women between the ages of 30 and 34 and one for women younger than 30.
Disclosure of potential conflicts of interest
No potential conflicts of interest were disclosed.
Additional information
Funding
References
- Rasmussen SA, Jamieson DJ. 2009 H1N1 influenza and pregnancy – 5 years later. N Engl J Med. 2014;371(15):1373–1375. doi:10.1056/NEJMp1403496. PMID:25295498.
- Dodds L, McNeil SA, Fell DB, Allen VM, Coombs A, Scott J, MacDonald N. Impact of influenza exposure on rates of hospital admissions and physician visits because of respiratory illness among pregnant women. CMAJ. 2007;176(4):463–468. doi:10.1503/cmaj.061435. PMID:17296958.
- Neuzil KM, Reed GW, Mitchel EF, Simonsen L, Griffin MR. Impact of influenza on acute cardiopulmonary hospitalizations in pregnant women. Am J Epidemiol. 1998;148(11):1094–1102. doi:10.1093/oxfordjournals.aje.a009587. PMID:9850132.
- Cortese MM, Baughman AL, Zhang R, Srivastava PU, Wallace GS. Pertussis hospitalizations among infants in the United States, 1993 to 2004. Pediatrics. 2008;121(3):484–492. doi:10.1542/peds.2007-1393. PMID:18310196.
- CDC. Immunization & Pregnancy. 2013. https://www.cdc.gov/vaccines/pregnancy/downloads/pregnancy-vaccination.pdf.
- Committee on Gynecologic Practice CoOP, Immunization Expert Work Group. Integrating Immunizations into Practice. Am College Obstet Gynecol. 2016;127(4):e104–7. doi:10.1097/AOG.0000000000001402.
- Ding H BC, Ball S, Fink RV, Williams WW, Fiebelkorn AP, Lu P, Kahn KE, D'Angelo DV, Devlin R, Greby SM. Influenza vaccination coverage among pregnant Women – United States, 2016–2017 influenza season. MMWR Morb Mortal Wkly Rep. 2017;66(38):1016–1022. doi:10.15585/mmwr.mm6638a2. PMID:28957044.
- Kahn KB CL, Ding H, Fiebelkorn AP, Liang JL, Ahluwalia IB, D'Angelo D, Ball SW, Fink R, Devlin R, Greby SM. Pregnant women and Tdap vaccination, internet panel survey, United States, April 2016. 2016; https://www.cdc.gov/vaccines/imz-managers/coverage/adultvaxview/tdap-report-2016.html. Accessed Sept. 7, 2017.
- Chamberlain AT, Berkelman RL, Ault KA, Rosenberg ES, Orenstein WA, Omer SB. Trends in reasons for non-receipt of influenza vaccination during pregnancy in Georgia, 2004–2011. Vaccine. 2016;34(13):1597–1603. doi:10.1016/j.vaccine.2016.01.058. PMID:26854909.
- Shavell VI, Moniz MH, Gonik B, Beigi RH. Influenza immunization in pregnancy: overcoming patient and health care provider barriers. Am J Obstet Gynecol. 2012;207(3Suppl):S67–74. doi:10.1016/j.ajog.2012.06.077. PMID:22920063.
- Eppes C, Wu A, You W, Cameron KA, Garcia P, Grobman W. Barriers to influenza vaccination among pregnant women. Vaccine. 2013;31(27):2874–2878. doi:10.1016/j.vaccine.2013.04.031. PMID:23623863.
- Moniz MH, Beigi RH. Maternal immunization. Clinical experiences, challenges, and opportunities in vaccine acceptance. Hum Vaccin Immunother. 2014;10(9):2562–2570. doi:10.4161/21645515.2014.970901. PMID:25483490.
- Fisher BM, Scott J, Hart J, Winn VD, Gibbs RS, Lynch AM. Behaviors and perceptions regarding seasonal and H1N1 influenza vaccination during pregnancy. Am J Obstet Gynecol. 2011;204(6 Suppl 1):S107–111. doi:10.1016/j.ajog.2011.02.041. PMID:21419386.
- Panda B, Stiller R, Panda A. Influenza vaccination during pregnancy and factors for lacking compliance with current CDC guidelines. J Matern Fetal Neonatal Med. 2011;24(3):402–406. doi:10.3109/14767058.2010.497882. PMID:20593974.
- Blanchard-Rohner G, Meier S, Ryser J, Schaller D, Combescure C, Yudin MH, Burton-Jeangros C, de Tejada BM, Siegrist CA. Acceptability of maternal immunization against influenza: the critical role of obstetricians. J Matern Fetal Neonatal Med. 2012;25(9):1800–1809. doi:10.3109/14767058.2012.663835. PMID:22339083.
- Ahluwalia IB, Jamieson DJ, Rasmussen SA, D'Angelo D, Goodman D, Kim H. Correlates of seasonal influenza vaccine coverage among pregnant women in Georgia and Rhode Island. Obstet Gynecol. 2010;116(4):949–955. doi:10.1097/AOG.0b013e3181f1039f. PMID:20859160.
- Bodeker B, Walter D, Reiter S, Wichmann O. Cross-sectional study on factors associated with influenza vaccine uptake and pertussis vaccination status among pregnant women in Germany. Vaccine. 2014;32(33):4131–4139. doi:10.1016/j.vaccine.2014.06.007. PMID:24928791.
- Mak DB, Regan AK, Joyce S, Gibbs R, Effler PV. Antenatal care provider's advice is the key determinant of influenza vaccination uptake in pregnant women. Aust N Z J Obstet Gynaecol. 2015;55(2):131–137. doi:10.1111/ajo.12292. PMID:25557858.
- Wiley KE, Massey PD, Cooper SC, Wood NJ, Ho J, Quinn HE, Leask J. Uptake of influenza vaccine by pregnant women: a cross-sectional survey. Med J Aust. 2013;198(7):373–375. doi:10.5694/mja12.11849. PMID:23581957.
- Yuen CY, Tarrant M. Determinants of uptake of influenza vaccination among pregnant women – a systematic review. Vaccine. 2014;32(36):4602–4613. doi:10.1016/j.vaccine.2014.06.067. PMID:24996123.
- Grimes HA, Forster DA, Newton MS. Sources of information used by women during pregnancy to meet their information needs. Midwifery. 2014;30(1):e26–33. doi:10.1016/j.midw.2013.10.007. PMID:24246969.
- Lagan BM, Sinclair M, Kernohan WG. Internet use in pregnancy informs women's decision making: A web-based survey. Birth. 2010;37(2):106–115. doi:10.1111/j.1523-536X.2010.00390.x. PMID:20557533.
- McArdle A, Flenady V, Toohill J, Gamble J, Creedy D. How pregnant women learn about foetal movements: sources and preferences for information. Women Birth. 2015;28(1):54–59. doi:10.1016/j.wombi.2014.10.002. PMID:25457375.
- Kraschnewski JL, Chuang CH, Poole ES, Peyton T, Blubaugh I, Pauli J, Feher A, Reddy M. Paging “Dr. Google”: does technology fill the gap created by the prenatal care visit structure? Qualitative focus group study with pregnant women. J Med Internet Res. 2014;16(6):e147. doi:10.2196/jmir.3385. PMID:24892583.
- Rodger D, Skuse A, Wilmore M, Humphreys S, Dalton J, Flabouris M, Clifton VL. Pregnant women's use of information and communications technologies to access pregnancy-related health information in South Australia. Aust J Prim Health. 2013;19(4):308–312. doi:10.1071/PY13029. PMID:24004661.
- Lagan BM, Sinclair M, Kernohan WG. What is the impact of the internet on decision-making in pregnancy? A global study. Birth. 2011;38(4):336–345. doi:10.1111/j.1523-536X.2011.00488.x. PMID:22112334.
- Ellingson M, Bonk CM, Chamberlain A. A survey-based study of Zika virus communication preferences among pregnant women in Georgia, United States. BMC Pregnancy Childbirth. 2017;17(1):32. doi:10.1186/s12884-017-1516-0. PMID:28088194.
- Peckham C. Medscape physician compensation report 2016. 2016; http://www.medscape.com/features/slideshow/compensaton/2016/public/overview?src=wnl_physrep_16040_mscpedit&uac232148CZ&impID=1045700&faf=1.
- Betsch C, Brewer NT, Brocard P, Davies P, Gaissmaier W, Haase N, Leask J, Renkewitz F, Renner B, Reyna VF, et al. Opportunities and challenges of Web 2.0 for vaccination decisions. Vaccine. 2012;30(25):3727–3733. doi:10.1016/j.vaccine.2012.02.025. PMID:22365840.
- Kata A. Anti-vaccine activists, Web 2.0, and the postmodern paradigm–an overview of tactics and tropes used online by the anti-vaccination movement. Vaccine. 2012;30(25):3778–3789. doi:10.1016/j.vaccine.2011.11.112. PMID:22172504.
- Huberty J, Dinkel D, Beets MW, Coleman J. Describing the use of the internet for health, physical activity, and nutrition information in pregnant women. Matern Child Health J. 2013;17(8):1363–1372. doi:10.1007/s10995-012-1160-2. PMID:23090284.
- Larsson M. A descriptive study of the use of the Internet by women seeking pregnancy-related information. Midwifery. 2009;25(1):14–20. doi:10.1016/j.midw.2007.01.010. PMID:17408822.
- Healy CM, Rench MA, Montesinos DP, Ng N, Swaim LS. Knowledge and attitiudes of pregnant women and their providers towards recommendations for immunization during pregnancy. Vaccine. 2015;33(41):5445–5451. doi:10.1016/j.vaccine.2015.08.028. PMID:26307234.
- Chamberlain AT, Koram AL, Whitney EA, Berkelman RL, Omer SB. Lack of availability of antenatal vaccination information on obstetric care practice web sites. Obstet Gynecol. 2016;127(1):119–126. doi:10.1097/AOG.0000000000001183. PMID:26646129.
- Livingston G, Cohn D. The New Demography of American Motherhood. 2010; http://www.pewsocialtrends.org/2010/05/06/the-new-demography-of american-motherhood/. Accessed 11/22/17, 2017.
- Sayakhot P, Carolan-Olah M. Internet use by pregnant women seeking pregnancy-related information: a systematic review. BMC Pregnancy Childbirth. 2016;16:65. doi:10.1186/s12884-016-0856-5. PMID:27021727.
- Tamhane AR, Westfall AO, Burkholder GA, Cutter GR. Prevalence odds ratio versus prevalence ratio: choice comes with consequences. Stat Med. 2016;35(30):5730–5735. doi:10.1002/sim.7059. PMID:27460748.